Prostaglandins play a major role in the inflammation process and the inhibition of prostaglandin production, especially production of PGG.sub.2, PGH.sub.2 and PGE.sub.2, has been a common target of anti-inflammatory drug discovery. However, common non-steroidal anti-inflammatory drugs (NSAIDs) that are active in reducing the prostaglandin-induced pain and swelling associated with the inflammation process are also active in affecting other prostaglandin-regulated processes not associated with the inflammation process. Thus, use of high doses of most common NSAIDs can produce severe side effects, including life threatening ulcers, that limit their therapeutic potential. An alternative to NSAIDs is the use of corticosteroids, which have even more drastic side effects, especially when long term therapy is involved.
Previous NSAIDs have been found to prevent the production of prostaglandins by inhibiting enzymes in the human arachidonic acid/prostaglandin pathway, including the enzyme cyclooxygenase (COX). Recently, the sequence of another heretofore unknown enzyme in the human arachidonic acid/prostaglandin pathway has been reported by T. Hla and K. Nielson, Proc. Natl. Acad. Sci, USA, 89, 7384 (1992) and named "cyclooxygenase II (COX II)" or "prostaglandin G/H synthase II". The discovery of an inducible enzyme associated with inflammation provides a viable target of inhibition which more effectively reduces inflammation and produces fewer and less drastic side effects. Cyclooxygenase II is inducible by cytokines or endotoxins and such induction is inhibited by glucocortoids (J. Masferrer, et al, Proc. Natl. Acad. Sci, USA, 89, 3917 (1992)). The 6-methoxy-2-napthylacetic acid metabolite of nabumetone has been found by E. Meade et al to selectively inhibit the COX II enzyme (J. Biol. Chem., 268, 6610 (1993)). In addition, Futaki et al (Prostaglandins, 47, 1 (1994)) have reported that N-(2-cyclohexyloxy-4-nitrophenyl)methanesulfonamide inhibits the COX II enzyme.
The substituted cyclopenta-2,4-dienyl compounds disclosed herein selectively inhibit cyclooxygenase II over cyclooxygenase I and relieve the effects of inflammation. These compounds, in addition, do not display substantial inhibition of cyclooxygenase I and produce a reduced amount of side effects.
Diarylcyclopentenes are described in a copending application, Ser. No. 08/146,359.
U.S. Pat. No. 4,946,993 to Cortes, describes the use of aryl substituted cyclopentadienes to form N-phosphonomethylglycine.
Allen et al [J. Org. Chem., 11, 268 (1946)] describe the formation of 3,4-diphenylcyclopentadiene.
Zimmerman and Pinock [J. Amer. Chem. Soc., 95, 3246 (1973)] describe the synthesis of 5,5-dimethyl-2,3-diphenylcyclopentadiene from diacetylenic compounds.
Hirao et al [J. Chem. Soc., Chem. Commun., 300 (1984)] describe the synthesis of norbornadienes from substituted cyclopentadienes and acetylenes. Specifically, 1,1'-(4,4-dimethyl-2,5-cyclopentadien-1,2-diyl)bis[4-methoxybenzene is described.